In general, in a plant control system, a system programmer provides a plant operator with a program for automatically operating a plant after creating the program as a control program for a plant control apparatus and tests and adjusts the program.
In order to safely control a plant, the system programmer has to install an interlock condition for startup and operation of plant equipment such as a rotary machine (a condition for permission of equipment operation) in the control program. Naturally, it is a matter of interest for the plant operator whether the interlock condition is satisfied. Therefore, it is demanded that the interlock condition is plainly presented to the plant operator.
As a plant control system in the past, a plant control system that displays an interlock state diagram when plant equipment abnormally stops is proposed (see Japanese Patent Laid-Open No. 11-242507).